Good nail clippers like these:
http://www.petsathome.com/shop/small-scissor-nail-clippers-for-cats-and-dogs-by-mikki-15576
Hold bunny still, either sat on your lap and pick up one paw at a time, or curve bunny backwards into the crook of your arm/elbow so feet are pointing into the air.
If the nails are white/pale you will see the live part of the nail (pink blood supply called the 'quick') and so you cut a good few mm above this, best to take off little by little to begin with if you're not used to doing it, rather than too much in one go. If you nick the quick the nail will bleed and bunny will flinch. You can stop the blood by holding on a cotton pad and applying pressure or using a styptic pencil or cornflour.
Dark/black nails - shining a torch through can help to identify the quick.
If you have someone who can help you might find this easier to begin with, otherwise a vet or VN will do it for you for a small charge.
Don't forget - 4 nails on back feet, 5 on front!